[PATCH 05/11] omap_vout: fix potential Spectre variant 1
From: Gustavo A. R. Silva
Date: Mon Apr 23 2018 - 13:42:08 EST
index can be controlled by user-space, hence leading to a
potential exploitation of the Spectre variant 1 vulnerability.
Smatch warning:
drivers/media/platform/omap/omap_vout.c:1062 vidioc_enum_fmt_vid_out() warn: potential spectre issue 'omap_formats'
Fix this by sanitizing index before using it to index
omap_formats.
Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
drivers/media/platform/omap/omap_vout.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/media/platform/omap/omap_vout.c b/drivers/media/platform/omap/omap_vout.c
index 5700b78..1a7ec39 100644
--- a/drivers/media/platform/omap/omap_vout.c
+++ b/drivers/media/platform/omap/omap_vout.c
@@ -51,6 +51,8 @@
#include "omap_voutdef.h"
#include "omap_vout_vrfb.h"
+#include <linux/nospec.h>
+
MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("OMAP Video for Linux Video out driver");
MODULE_LICENSE("GPL");
@@ -1059,6 +1061,7 @@ static int vidioc_enum_fmt_vid_out(struct file *file, void *fh,
if (index >= NUM_OUTPUT_FORMATS)
return -EINVAL;
+ index = array_index_nospec(index, NUM_OUTPUT_FORMATS);
fmt->flags = omap_formats[index].flags;
strlcpy(fmt->description, omap_formats[index].description,
sizeof(fmt->description));
--
2.7.4